1. Technical Field
This application relates to mobile telecommunications systems in general, having particular application in UMTS (Universal Mobile Telecommunications System) in general, and to an apparatus and method for handling system information in mobile telecommunications system user equipment.
2. Description of the Related Art
The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
In a typical cellular radio system, mobile user equipment (UE) communicates via a radio access radio network (RAN) to one or more core networks. User equipment (UE) comprises various types of equipment such as mobile telephones (also known as cellular or cell phones), lap tops with wireless communication capability, personal digital assistants (PDAs) etc. These may be portable, hand held, pocket sized, installed in a vehicle etc and communicate voice and/or data signals with the radio access network.
In the following, reference will be made to UMTS and to particular standards. However it should be understood that the invention is not intended to be limited to any particular mobile telecommunications system.
The radio access network covers a geographical area divided into a plurality of cell areas. Each cell area is served by at least one base station, which in UMTS may be referred to as a Node B. Each cell is identified by a unique identifier which is broadcast in the cell. The base stations communicate at radio frequencies over an air interface with the UEs within range of the base station. Several base stations may be connected to a radio network controller (RNC) which controls various activities of the base stations. The radio network controllers are typically connected to a core network.
UMTS is a third generation public land mobile telecommunication system. Various standardization bodies are known to publish and set standards for UMTS, each in their respective areas of competence. For instance, the 3GPP (Third Generation Partnership Project) has been known to publish and set standards for GSM (Global System for Mobile Communications) based UMTS, and the 3GPP2 (Third Generation Partnership Project 2) has been known to publish and set standards for CDMA (Code Division Multiple Access) based UMTS. Within the scope of a particular standardization body, specific partners publish and set standards in their respective areas.
Consider a wireless mobile device, generally referred to as user equipment (UE), that complies with the 3GPP specifications for the UMTS protocol. The 3GPP 25.331 specification, v.3.15.0, referred to herein as the 25.331 specification, addresses the subject of UMTS RRC (Radio Resource Control) protocol requirements between the UMTS Terrestrial Radio Access Network (UTRAN) and the UE.
In mobile telecommunications system, measurements are taken periodically to ensure that the mobile device is in communication with the most appropriate part of the network. The network also transmits, in either a broadcast or a dedicated fashion, system information that mobile device uses to control the communication with the network.
The system information may be transmitted as system information blocks (SIBs), each of which has a defined purpose. System information elements (IEs) are broadcast in the system information blocks. A master information block may also be implemented and may optionally also contain reference and scheduling information to one or more scheduling blocks, which give references and scheduling information for additional system information blocks. Scheduling information for a system information block may be included in either the master information block or one of the scheduling blocks.
Table 8.1.1. of the 25.331 specification provides a specification of the system information blocks transmitted by the network in a UMTS network. SIB 11 is used in Idle Mode and in connected mode when the UE is in one of the following states: CELL_FACH, CELL_PCH or URA_PCH. SIB 12 is used in connected mode when the UE is in one of the following states: CELL_FACH, CELL_PCH or URA_PCH. According to Table 8.1.1, if system information block type 12 is not broadcast in a cell, the connected mode UE shall read System information block type 11: If some of the optional IEs are not included in System information block type 12, the UE shall read the corresponding IEs in System information block type 11.
There are occasions when both SIB 11 and SIB 12 are transmitted and one SIB contains an IE that is also contained in the other SIB. For instance, in clause 8.1.1.6.11 of the 25.331 standard it is stated that, when SIB 11 is received, the UE acts upon the received IE “Intra-frequency cell info list”/“Inter-frequency cell info list”/“Inter-RAT cell info list” as described in subclause 8.6.7.3. It is also stated in clause 8.1.1.6.11 that, if in connected mode and System Information Block type 12 is indicated as used in the cell, the UE will read and act on information sent in System Information Block type 12 as indicated in clause 8.1.1.6.12. Clause 8.1.1.6.12 then says that, when SIB 12 is received, the UE acts upon the received IE “Intra-frequency cell info list”/“Inter-frequency cell info list”/“Inter-RAT cell info list” as described in subclause 8.6.7.3.
There are thus proposed strategies for handling system information in user equipment. A number of such strategies are detailed below.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of an apparatus and method for handling system information in mobile telecommunications system user equipment.